Electron-longitudinal-phonon coupling in a transition metal: Ta

Recent tunneling studies of tantalum using a proximity technique reveal stronger coupling to the longitudinal modes relative to the transverse modes than observed previously for any transition metal. This result has implications for modeling the electron-phonon coupling mechanism and for future tunneling investigations. We obtain parameter values for Ta of $\text{λ = 0.73, μ}{}_{\mathrm{ph}}{}^1\text{= 0.10}$,in agreement with optimized conventional results.